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Decided to try the Ethanol free stuff, see if there is a marked improvement in performance, etc. ...
https://www.pure-gas.org/station?station_id=15180
i love the puregas app .. really helps to find ethanol free when i am out of my area. ethanol free is much easier to find these days thanks to the boaters and lawn care guys who do not tolerate the ethanol. you can thank them for bringing back the pure gas.

i am not a chemist but i have read about the deterioration of ethanol when stored, its affinity for water and its effect on rubber. those are some of the reasons lawn care companies and boaters avoid the stuff.
i prefer the ethanol free 90 from royal farms to the ethanol free from wawa, but i don't think i notice any better engine performance. as best i understand, the issue with ethanol is that it eats rubber and allows water to condense in the tank. i was advised that if your engine is older than 2000, then you should be using ethanol free gas.
 

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I experimented with diff grades of fuel over the summer w my 05 330xi. I didnt notice any appreciable change in performance between any of them, but the fuel economy varied by a couple mpg.

90 oct. nonE = 31-32 mpg
93 oct. = 29-30 mpg
89 oct. = 28-29 mpg

Those are highway figures. For the extra cost associated with the nonE it didnt make sense based on fuel economy to pay an extra 30 cents/gal.

Sent from my SM-G950U using Tapatalk
 

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'03 325iT Mystic Blau
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For our cars there is no reason to use ethanol free. These cars were designed to have ethanol in the fuel system, if you owned say and E30 or E36 then it would be recommended to run ethanol free because it would stop damage to valve seats and seals.
You must be thinking of leaded gas, and even then E30 and E36 are too new to need it. Ethanol doesn't have any effect on valve seats or seals.
 

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ok so say bmw plastic and rubber are impervious to ethanol .. but what about the water/condensation issue?

ethanol is ok if you drive the car every day, but not as stable as regular gas.
 

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ok so say bmw plastic and rubber are impervious to ethanol .. but what about the water/condensation issue?

ethanol is ok if you drive the car every day, but not as stable as regular gas.
It's not going to be that big of an issue. I've left my M3 parked for the better part of a year, and had no trouble afterwards.
 

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Discussion Starter #9
The next time you replace the fuel pump get a piece of clear 3/8 tubing plastic or glass, just needs to be stiff. Stand it up in the gas tank and cover the top with your finger, pull it out and see if and how much water you have in the bottom. If its near the halfway mark, you definitely need to remove it. Alternately you could add some food coloring, which is soluble in water but not gas to the tank and see how big the glob in the bottom is.
 

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The next time you replace the fuel pump get a piece of clear 3/8 tubing plastic or glass, just needs to be stiff. Stand it up in the gas tank and cover the top with your finger, pull it out and see if and how much water you have in the bottom. If its near the halfway mark, you definitely need to remove it. Alternately you could add some food coloring, which is soluble in water but not gas to the tank and see how big the glob in the bottom is.
thanks i will try this. good timing since i am hoping that replacing the fuel filter and fuel pump will solve the occasional misfire.
 
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